The present invention relates to a hinge structure for an electronic apparatus such as a laptop type personal computer, a word-processor, and the like.
FIG. 1 is a sectional view of one of a pair of hinges of a conventional information processing system disclosed in Japanese Unexamined Patent Publication (JP-A) No. 237315 of 1992. The pair of hinges of this information processor causes a cover having a liquid crystal display (LCD) disposed therein to be rotatably supported on a main body casing having a keyboard, CPU and etc. disposed therein.
In FIG. 1, a bush 2 made of a material having a comparatively large coefficient of friction is fitted in a central shaft 1 which supports the cover (not shown) and which is strong enough to withstand a torque applied thereon. Further, the bush 2 is covered by a cylindrical housing 3. A rotary support 4 is formed integral with the cover and is provided with a hinge receiving bore 5 at one end thereof. The housing 3 is received within the hinge receiving bore 5. A flat portion 1a formed at the top end of the central shaft 1 is inserted into, and supported by, a hole 9 of a hinge metal 8 fixed to the main body casing 6 by means of a screw 7. A rib 10 formed on the main body casing 6 supports the rotary support 4.
In the case of this information processing system, the operator may open and close the cover about a hinge so as to optionally adjust the angle of orientation of the cover while he looks at the screen of the liquid crystal display disposed within the cover.
A first drawback of the above-described conventional hinge structure resides in that in order to prevent the deformation of the hinge metal 8 for fixing the bush 2, it is necessary for the hinge metal 8 to have a sufficient size and thickness to satisfy the rigidity thereof. Accordingly, it is difficult to make the information processing system compact, thin and light in weight for the sake of portability.
A second drawback of the above-described conventional hinge structure resides in that the hinge metal 8 and the screw 7 must be used for preventing the rotation of the bush 2 and for fixing the bush 2. Consequently, the cost of parts such as the hinge metal 8 and the screw 7 and the cost of assembling these parts are needed to thereby increase the manufacturing cost.